On Tue, 2005-12-20 at 14:39 +0100, Jens Axboe wrote:
> > Should be an easy check to add. In fact, I'll resend both patches with
> > that in place if you want.
>
> There's still the quirky problem of forcing a locked tray out. In some
> cases this is what you want, if things get stuck for some reason or
> another. But usually the tray is locked for a good reason, because there
> are active users of the device.
>
> Say two processes has the cdrom open, one of them doing io (maybe even
> writing!), the other could do a CDROMEJECT now and force the ejection of
> a busy drive.
But that's possible now with "eject -s" as long as you have write access
to it. Most users are using "eject -s" anyway.
You can't stop this from happening. However, the fact is that a lot of
devices (iPod's being the most popular) require this to work.
Here's the patch. Currently it will not even try the
ALLOW_MEDIUM_REMOVAL unless they have write access (to avoid returning
an uneeded error for people using eject -r that isn't patched to open
the device O_RDRW). However, I still changed the __blk_send_generic()
function to use verify_command().
Signed-off-by: Ben Collins <[email protected]>
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 382dea7..df259f7 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -442,11 +442,54 @@ error:
return err;
}
+
+/* Send basic block requests */
+static int __blk_send_generic(struct file *file, request_queue_t *q, struct gendisk *bd_disk, int cmd, int data)
+{
+ struct request *rq;
+ int err;
+
+ rq = blk_get_request(q, READ, __GFP_WAIT);
+ rq->flags |= REQ_BLOCK_PC;
+ rq->data = NULL;
+ rq->data_len = 0;
+ rq->timeout = BLK_DEFAULT_TIMEOUT;
+ memset(rq->cmd, 0, sizeof(rq->cmd));
+
+ rq->cmd[0] = cmd;
+ rq->cmd[4] = data;
+ rq->cmd_len = 6;
+
+ if (file) {
+ err = verify_command(file, rq->cmd);
+ if (err)
+ goto send_error;
+ }
+
+ err = blk_execute_rq(q, bd_disk, rq, 0);
+
+send_error:
+ blk_put_request(rq);
+
+ return err;
+}
+
+/* START_STOP just needs read only, so safe */
+static inline int blk_send_start_stop(request_queue_t *q, struct gendisk *bd_disk, int data)
+{
+ return __blk_send_generic(NULL, q, bd_disk, GPCMD_START_STOP_UNIT, data);
+}
+
+/* ALLOW_MEDIUM_REMOVAL needs write access */
+static inline int blk_send_allow_medium_removal(struct file *file, request_queue_t *q, struct gendisk *bd_disk)
+{
+ return __blk_send_generic(file, q, bd_disk, GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, 0);
+}
+
int scsi_cmd_ioctl(struct file *file, struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
{
request_queue_t *q;
- struct request *rq;
- int close = 0, err;
+ int err;
q = bd_disk->queue;
if (!q)
@@ -564,19 +607,20 @@ int scsi_cmd_ioctl(struct file *file, st
err = sg_scsi_ioctl(file, q, bd_disk, arg);
break;
case CDROMCLOSETRAY:
- close = 1;
+ err = blk_send_start_stop(q, bd_disk, 0x03);
+ break;
case CDROMEJECT:
- rq = blk_get_request(q, WRITE, __GFP_WAIT);
- rq->flags |= REQ_BLOCK_PC;
- rq->data = NULL;
- rq->data_len = 0;
- rq->timeout = BLK_DEFAULT_TIMEOUT;
- memset(rq->cmd, 0, sizeof(rq->cmd));
- rq->cmd[0] = GPCMD_START_STOP_UNIT;
- rq->cmd[4] = 0x02 + (close != 0);
- rq->cmd_len = 6;
- err = blk_execute_rq(q, bd_disk, rq, 0);
- blk_put_request(rq);
+ err = 0;
+
+ /* We don't even want to try the
+ * ALLOW_MEDIUM_REMOVAL unless the user has write
+ * access. The START_STOP will fail if the drive
+ * needs ALLOW_MEDIUM_REMOVAL anyway. */
+ if (!(file->f_mode & FMODE_WRITE)) {
+ err |= blk_send_allow_medium_removal(file, q, bd_disk);
+ err |= blk_send_start_stop(q, bd_disk, 0x01);
+ }
+ err |= blk_send_start_stop(q, bd_disk, 0x02);
break;
default:
err = -ENOTTY;
--
Ben Collins <[email protected]>
Developer
Ubuntu Linux
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